Rainaa and Renee Smith know they are hunted. They've known since they were small children that they are hunted and why. What they don't know, however, is what it feels like to be loved and love in return. That is, they didn't know until they came to Hogwarts and made life-long bonds with the people they least expected.
(I don't consider it to be Mary-Su...the OCs are nothing like me...if you do, though, that's fine)